第18卷第3期 2018年6月
流动与传递 aa
e
过程工程学报
The Chinese Joumal of Process Engineering
Vol.18 No.3 June 2018
DOI: 10.12034/j.issn.1009-606X.217329
内置螺旋挡板流化床颗粒停留时间分布
都艺伟，吴新，刘道洁，李军辉
(东南大学能源热转换及其过程控制测控教育部重点实验室，江苏南京210096)
摘要：采用脉冲示踪法在内置螺旋挡板冷态鼓泡流化床上研究了螺旋挡板、加料速率、流化风速、颗粒粒径和床料高度对颗 0.085，螺旋挡板可有效抑制颗粒返混，增大颗粒运动的平推流趋势：加料速率增大为约2倍时，停留时间减小为约50%，流动更趋向于平推流；床料高度增加，颗粒返混加剧，颗粒平均停留时间及无量纲方差均增大，颗粒运动向全混流靠近；随流化风
速增大，颗粒平均停留时间变长：实验范围内，颗粒粒径对颗粒停留时间分布影响不大. 关键词：螺旋挡板：流化床双床结构：颗粒；停留时间分布
中图分类号：TQ021.4
文献标识码：A
文章编号：1009-606X(2018)03048407
ResidenceTimeDistributionofParticles inFluidizedBed withSpiral Internal
YiweiDU,XinWU',DaojieLIU,Junhui LI
(Key Laboratory of Energy Conversion and Process Control of Ministry of Education,
Southeast University, Nanjing, Jiangsu 210096, China)
Abstract: Effects of spiral intermal, solid feeding rate, fluidized gas velocity, particle size and bed height on the particle residence time distribution were investigated in a cold bubbling fluidized bed using the tracer technique. The results showed that the dimensionless variance of particle residence time reduced from 0.558 without spiral intermal to 0.085 with a spiral internal, indicating that the spiral intermal helped restrain the back mixing of particles and made the flow approach the plug flow. When the solid feeding rate was doubled the residence time of particles decreased by approximately 50% and the flow was closer to plug flow. As the increased bed height caused severe back mixing, both average residence time and dimensionless variance increased and the solid flow tended to be complete stirred flow. The average residence time of particles extended with the increasing of fluidized gas velocity. Particle size had a little effect on the residence time distribution under present experimental conditions.
Key words: spiral internal; dual fluidized bed; particle; residence time distribution
1前言
流化床干燥机在干燥领域应用广泛，各种机型存在一定不足：振动流化床干燥机结构复杂、振动部件易损坏；离心流化床干燥机的转鼓能耗大、维修困难；搅拌流化床干燥机的搅拌装置耗能多、易损坏：卧式流化床干燥机占地面积大、床料返混粘结严重：立式流化床干燥机不能连续干燥并存在严重的沟流、腾涌内置螺旋挡板流化床双床结构可连续进出料，无运动部件，结构简单紧凑、能耗低、故障率低，且可使颗粒运动更均匀
收稿日期：20170908，修回日期：20171026
基金项目：国家重点研发计划资助项目(编号：2016YFB0600602)
一致，用作流化床干燥器有显著优势，结构如图1所示，可根据工艺需要选择外壁或中心进出料.床体内的螺旋通道及布风板上的导向风帽可使物料沿螺旋通道均匀一致向前运动；两层床体叠加的结构使颗粒在流化床内的停留时间加倍；正常运行时，流化风先经过下层床体对由上床层落下的床料进行干燥，温度较高、湿度较低的流化风再经过上层床体对刚进入流化床的湿颗粒进行预干燥，充分利用流化风的温度和干度，明显减小能耗。流化床内螺旋挡板结构可有效抑制颗粒返混["]，并使颗粒在流化床内的停留时间分布更均匀，对颗粒物料
作者简介：都艺伟(1991-)，女，山东省烟台市人，硕士研究生，动力工程专业，E-mail:1559318059@qq.com：吴新，通讯联系人，E-mail:
wuxin@seu.edu.cn
引用格式：都艺伟，吴新，刘道洁，等，内置媒能挡板流化床颗粒停留时间分布，过程工程学报，2018,18(3)：484-490
DuY W, Wu X, Liu DJ, et al. Residence Time Distribution of Particles in Fluidized Bed with Spirnal Intemal (in Chinese), Chin.J.Process Eng 2018,18(3): 484490, DOI:10.12034/j.issn.1009-606X.217329,
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