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

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

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。

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. Threephase 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/Ho） 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-distri- bution 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/Ho increases incipiently slowly and then quickly for lower density system. However, the variation of H/H0 is opposition for higher density system.