下行移动床颗粒流动特性冷模试验研究

㊀第25卷第2期

洁净煤技术

Vol．25㊀No．2㊀㊀2019年

3月

Clean Coal Technology

Mar.㊀

2019㊀

下行移动床颗粒流动特性冷模试验研究

杨㊀帆,郑㊀雄,李建波,王泉海,薛景文,陆㊀凯,卢啸风

(重庆大学低品位能源利用技术及系统教育部重点实验室,重庆㊀400044)

摘㊀要:针对目前大宗固体颗粒余热回收常存在换热不充分㊁气固流动阻力大㊁回收得到的余热质量较低等问题,提出了一种气固交叉流动移动床高温颗粒冷却技术方案,并在自行设计的工业级试验装置上利用CFB 锅炉炉渣完成了冷态条件下的颗粒流动特性试验研究㊂通过取样与高速摄影仪拍摄相结合的方式对颗粒流动特性进行测量,分析讨论了颗粒流通截面尺寸对颗粒流动特性的影响和错流段空截面风速对颗粒流动稳定性的影响㊂结果表明:直流段截面中部颗粒下行速度基本一致,在忽略边壁影响的条件下,计算得到直流段正面和侧面流动指数M F1均大于0．3,认为直流段颗粒流动为整体流状态;通过对不同位置颗粒取样,发现各取样点颗粒的质量分数最大相差约14．4%,在实际工程中可认为扩大段颗粒整体流动均匀,但不同位置的颗粒粒径分布存在差异;随着横向风速的增大,颗粒携带速率增大,流过下行移动床的水平风速不能超过1．45m /s ㊂关键词:移动床;颗粒流;流动特性;冷模试验

中图分类号:TQ051．5㊀㊀㊀文献标志码:

A㊀㊀㊀文章编号:1006-6772(2019)02-0089-07

移动阅读

收稿日期:2019-01-02;责任编辑:白娅娜㊀㊀DOI :10.13226/j.issn.1006-6772.19010201基金项目:国家重点研发计划资助项目(2016YFB0600201)

作者简介:杨㊀帆(1990 ),男,湖北恩施人,硕士研究生,研究方向为颗粒余热回收㊂E -mail :20120734@ ㊂通讯作

者:卢啸风,男,教授,主要从事循环流化床锅炉㊁洁净煤燃烧技术相关研究㊂E -mail :xfluke@

引用格式:杨帆,郑雄,李建波,等.下行移动床颗粒流动特性冷模试验研究[J].洁净煤技术,2019,25(2):89-95.

YANG Fan,ZHENG Xiong,LI Jianbo,et al.Experimental study on the particle flow characteristics in a downward moving bed[J].Clean Coal Technology,2019,25(2):89-95.

Experimental study on the particle flow characteristics in a

downward moving bed

YANG Fan,ZHENG Xiong,LI Jianbo,WANG Quanhai,XUE Jingwen,LU Kai,LU Xiaofeng

(Key Laboratory of Low -Grade Energy Utilization Technology &System ,Chongqing University ,Chongqing ㊀400044,China )

Abstract :In terms of the problems that exsit in the waste heat recovery of bulk solid particles,such as insufficient heat transfer,high gas -solid flow resistance and low quality of the waste heat recovery,a cooling technology for high temperature particle using gas -solid cross -flow moving bed was proposed in this study.The experimental study on particle flow characteristics under cold operating conditions was car-ried out with CFB boiler ash via a self -designed industrial experimental apparatus.Particle flow characteristics were measured by sampling and high -speed photography.The effects of the cross -sectional size of the particle flow on particle flow characteristics and cross -sectional gas speed on particle flow stability were analyzed and discussed.The results show that the downward velocity of particles in the central part of the straight flow section is basically constant.Neglecting the influence of the side walls,the calculated flow index M F1of the front and side section of straight flow section exceed 0.3,which show that the particle flow was considered as a bulk flow under the experimental conditions.By sampling the particles at different locations,it is found that the maximum difference of particle mass ratio is about 14.4%,which could be considered that the particle flow in the enlarged section was uniform in practical engineering,while the particle size distri-bution at different locations is different.With increasing the transverse air velocity,the particle carrying rate increases.The air velocity in the downward moving bed can not exceed 1.45m /s.

Key words :moving bed;granular flow;flow characteristic;experimental study

0㊀引㊀㊀言

大宗固体颗粒余热回收问题广泛存在于建

材[1-2]㊁电力[3-4]㊁冶金[5-6]㊁化工[7-8]等行业,如干法粒化后的高炉渣颗粒温度在1000ħ以上[5],陶粒生产企业生产的陶粒温度可达800ħ[9],大型循环

9

8