增压导向式喷动流化床流动特性的试验研究

Hydrodynamics of Spout Fluid Bed with a Draft Tube at Elevated Pressure

在内径２００ｍｍ，高３．５ｍ，６０°“Ｖ”形布风板的钢制试验装置上，采用密度为２４５０ｋｇ／ｍ３，粒径分别为（１．５～２．５）ｍｍ和（０．１～１．０）ｍｍ窄筛分玻璃珠，以及密度为２２００ｋｇ／ｍ３，粒径为（０．４５～６．０）ｍｍ的宽筛分溢流渣为物料，对各种压力下的导向式喷动流化床最小喷动流化速度、导向与环形区压降、中心喷泉高度以及颗粒循环量和气体旁路特性进行了试验研究。试验结果表明：最小喷动流化速度、导向与环形区压降以及中心喷泉高度与系统几何参数和操作参数密切相关，卷吸段气体射流的性质直接决定了颗粒循环量及其趋势，气体旁路的程度取决于卷吸段两股气流的相互作用。文章中用修正的弗劳德数归纳了中心喷泉高度试验关联式。

An experimental study on minimum spout fluidization velocity,pressure drop in draft tube and annulus zone,fountain height,solids circulation and bypassing of gases of spout fluid bed with a draft tube at elevated pressure has been performed in a 20 cm diameter,3.5 m height cylindrical steel column with 60° conical distributor.Two different diameter glass beads with 2 450 kg/m 3 ( d p=(1.5～2.5) mm, d p=(0.1～1.0) mm)and slag( ρ s=2 200 kg/m 3, d p=(0.45～6.0) mm)have been used as bed material.The minimum spout fluidization velocity,fountain height and overall prssure drop have been found to be strongly dependent on geometric parameters and operation conditions.The solids circulation trends are shown to be a direct result of the phenomena of entrainment jetting occuring in the entrainment zone.The extent of these bypassings is a result of the interactions between these gases in the entrainment zone.An experimental correlation with modified Fr has been proposed for predicting fountain height.