新型组合烧焦装置烧焦管内固体颗粒混合特性的研究

采用脉冲磷光颗粒示踪法对一套新型组合烧焦装置的烧焦管(内径186mm,高10m)内固体颗粒的停留时间分布进行了测试,研究了烧焦管内固体颗粒的混合特性。结果表明,在烧焦管表观气速为6.39m/s、烧焦管内颗粒循环强度为101.7kg/(m2.s)的条件下,在检测探头距示踪剂注入位置1.0m处,颗粒停留时间分布呈较对称的单峰分布,从烧焦管轴心向边壁靠近,其峰高差别较大;而在检测探头距示踪剂注入位置4.0m及9.4m处,颗粒的停留时间分布曲线由一个尖而高的前峰和长拖尾所组成,曲线的峰高基本一致,表明颗粒沿轴向以弥散颗粒和颗粒团的形式扩散,颗粒沿径向的混合较均匀。对1.0m检测距离内的颗粒扩散行为建立了二维轴、径向扩散模型,对4.0m以上检测距离的颗粒扩散行为建立一维轴向两组分扩散叠加模型,模型预测值与试验值吻合较好。

SOLID PARTICLES MIXING BEHAVIOR IN COKE-BURNING RISER OF A NOVEL COMBINED COKE BURNER

The particles mixing behavior in the coke-burning riser(186mm ID,height 10m)of a novel combined coke burner was studied through measuring the residence time distributions(RTD)of particles by using phosphor particles as tracers.Test results showed that the RTD curves of particles within 1.0m of tracer injection were unimodal and the peak height decreased from the center to the wall.Moreover,the RTD curves of particles within 4.0m and 9.4m of tracer injection were sharp-high leading peak with a long tail,and these peak heights were nearly the same.The particles mixing mechanism in the riser could be explained by the dispersion of dispersed particles and clusters.A radial diffusion model and an axial superposition model were established to predict the particle diffusion characteristics within 1.0m,4.0m and 9.4m detecting distance of the riser,respectively.The predicted values were in good agreement with the experimental results.