导向管充气喷动床干燥性能的研究

Drying Characteristics of Draft Tube Spouted Bed with Aeration

在普通喷动床环形区底部引入“充气”可消除环形区底部颗粒“死区”的影响，并能改善环形区气固间的热、质传递．在内径９６ｍｍ的夹套式干燥器中，以绿豆为实验物料，空气为干燥介质，采用间歇操作方式，考虑了充气和喷动气速以及热通量的影响，对导向管充气喷动床的干燥性能进行了研究．研究表明随着充气速度的增加，干燥速率先增大后减小；随着喷动气速的增加干燥速率先增加很快后缓慢增加；随着热通量的增加，干燥速率呈直线增加趋势．对实验数据分析得到：在最大允许充气速度范围内，有充气的导向管喷动床干燥器比没有充气时的导向喷动床的干燥效果明显增加，说明导向充气喷动床更有使用价值．

The“dead zone”of particle located at the bottom of annulus can be eliminated,and the effectiveness of solidgas contact,mass and heat transfer can be improved by introducing an auxiliary(aeration or fluidization)fluid into the annular region through a distributor.The drying characteristics of a draft tube spouted bed with aeration(DTSAB),such as the effect of aerating,spouting velocity and heat flux,in which green beans were used as experimental material,and air as drying medium,by using batch operation,were investigated in a jacket dryer of 96 mm I·D.The result indicates that:drying rate first increases as increasing aerating velocity and then decreases;increases as spouting velocity and furthur without change;and increases as heat flux.The drying rate over the constant rate period for a DTSAB is 2.15 times of that for a DTSB.This can be used as reference for the designing and operation of a DTSAB dryer.