摘要
在368mm×368mm方形气固流化床中采用FCC颗粒研究了局部颗粒浓度分布的基本行为,实验测试了不同高度床层截面上的局部颗粒浓度分布。结果表明:局部颗粒浓度在床层中心最小,向外逐渐增加,边壁处颗粒浓度急剧增加到最大;表观气速(Ug)较低时,床层截面内不同方向上颗粒浓度分布的差异较大;随表观气速增大,床层截面内不同方向上的颗粒浓度分布规律趋于一致。局部流动结构的转变首先发生于床层中心,然后再向边壁逐渐扩展。颗粒浓度概率密度分布曲线(PDD)表明在湍动流态化下稳定的两相流动结构已被打破。
In order to study the basic behaviors of local solid concentration in a square gas-solid fluidized bed reactor,the distributions of local solid concentrations on different axial levels in a 368 mm×368 mm square fluidized bed with FCC particles were measured.The results show that the distribution of local solid concentration in the cross-section of the square fluidized bed is non-uniform.The local solid concentration at center of the square reactor is lowest and increases gradually with the increase of distance from the center;near the wall of the reactor,the solid concentration reaches its maximum value.Under the lower superficial gas velocity,the distributions of local solid concentrations in different lateral directions are not axial symmetrical in the bed cross-section.With the increase of the superficial gas velocity,the distributions of local solid concentrations in the bed cross-section tend to be axial symmetrical in different directions.The transition from bubbling fluidization to turbulent fluidization is a process gradually extending from the bed center to the bed wall.The particle density distribution（PDD） curves show that,under the turbulent fluidization,the steady two-phase flow has been broken.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2010年第5期783-788,共6页
Journal of Chemical Engineering of Chinese Universities
基金
四川省教育厅重大培育项目(07ZZ019)
关键词
气固流化床
方形
颗粒浓度
局部流型
gas-solid fluidized bed
square
solid concentration
local flow regime
