摘要
在环隙下料式流化床-提升管耦合反应器大型冷模实验装置中,研究了提升管和环隙下料管内FCC颗粒截面平均固含率（εp）的轴向分布.结果表明,流化床区域内pe随操作气速增大而减小,提升管区域可分为充分发展区（3.91～6.81 m）和约束返混区（6.81～8.60 m）,提升管区域内εp随操作气速增大而增大,操作气速小于0.7 m/s时,εp沿轴向分布均匀;其大于0.7 m/s时,约束返混区的pe明显增大.在环隙下料管内,由于受窜气的影响,颗粒沿重力场流动阻力增大.操作气速小于0.75 m/s时,环隙下料管内εp沿轴向分布较均匀;其大于0.75 m/s时,变径段出现脱空现象.总体上,εp沿轴向向下略有增加,颗粒可顺畅通过环隙下料管循环返回流化床内.确定了提升管区域内εp沿轴向分布的经验模型,计算值与实验值吻合较好.
The axial distribution of solids hold-up in a large scale cold model annulus fluidized bed？riser coupled reactor was studied. The results showed that in the fluidized bed zone, the averaged cross-sectional solids hold-up（p？） decreased with increasing of superficial gas velocity. The riser zone could be divided into two zones, fully developed zone（3.91？6.81 m） and back-mixing zone（6.81？8.60 m）, p？ increased with increasing of superficial gas velocity. When the gas velocity was less than 0.7 m/s, the distribution of p？ was uniform, when the gas velocity was greater than 0.7 m/s, p？ in back-mixing zone increased. In the annulus discharging duct, under the influence of gas bypass, the flow was concurrent with the gravity field with increasing of fluid resistance. When the gas velocity was less than 0.75 m/s, the distribution of p？ was uniform, when the gas velocity was greater than 0.75 m/s, disengaging occurred in the cone-shaped sections. On the whole, the distribution of p？ in the annulus discharging duct was uniform, p？ increased slightly with decreasing of height of the annulus discharging. The particles could complete the circular flow back into the fluidized bed through the annulus discharging duct smoothly. Furthermore, the empirical models for estimating the axial distribution of p？ were established based on experimental data, which were in good agreement with the experimental data.
出处
《过程工程学报》
CAS
CSCD
北大核心
2016年第2期210-215,共6页
The Chinese Journal of Process Engineering
关键词
耦合流化床
下料管
固含率
轴向分布
coupled fluidized bed
discharging duct
solids hold-up
axial distribution
