气-液-固三相流化床气体分布器区局部相含率和床层膨胀比的实验研究

在内径150 mm,高4 350 mm的三相流化床中,分别以空气、水和0.48 mm、1.25mm的玻璃珠及1.45 mm的苯乙烯树脂为气相、液相和固相,应用开发的微电导探针测试技术同时测得三相局部含率,并对气体分布器区的局部相含率和床层膨胀比(H/H0)进行了实验研究,考察了固体颗粒的粒径、密度及表观液速和气速对床层膨胀比的影响。研究发现,在距气体分布器轴向一定距离范围内,三相局部含率的径向分布存在明显的不对称分布;随着轴向距离的增加,局部气含率的径向不对称分布逐渐消失,局部固含率的径向不对称分布变化不明显;床层膨胀比随表观气速和液速的增大而增大;较低密度颗粒系统的H/H0开始增加缓慢,后来增加很快;较高密度颗粒系统的H/H0开始迅速增加,后来增加缓慢。

Study on Three Phase Local Holdups and Expansion Ratio in Gas Distributor Region of G-L-S Three Phase Fluidized Bed

The experiments were carried out with air,water,and 0.48 mm,1.25 mm glass beads,1.45 mm styrene resin as gas,liquid and solid phases,respectively.Three-phase local holdups were measured simultaneously with micro-conductivity probe technique at on four levels with at 200 mm intervals along the three-phase fluidized bed with 150 mm in diameter and 4 350 mm in height.Local phase holdups and bed expansion ratio(H/H0) near gas distributor region were investigated.H/H0 was also studied with various kinds of particle,superficial gas velocity and liquid velocity.It was shown that radial profiles of the three phase local holdups were severe radial mal-distribution near the gas distributor.Also,the experimental results indicated that such radial mal-distribution of local gas holdup was disappeared with increasing axial height,corresponding transition to symmetry distribution.H/H0 increases with increasing superficial gas velocity and liquid velocity.H/H0 increases incipiently slowly and then quickly for lower density system.However,the variation of H/H0 is opposition for higher density system.