摘要
为解决锅炉运行中水侧的结垢和强化传热问题,本文将流化床换热防垢节能技术和锅炉相结合,设计并构建了冷模液-固循环流化床锅炉.选用不同粒径的聚甲醛(POM)颗粒作为惰性固体颗粒,利用CCD图像测量和处理系统,对循环流化床锅炉中的颗粒流化和分布开展了可视化研究.考察了锅炉回水流量、颗粒加入量和颗粒粒径等操作参数的影响.研究结果表明,在适当的条件下,聚甲醛颗粒可以在锅炉系统中实现正常的循环,并在上升管束中较好地分布,但同时也存在颗粒在锅筒中堆积的问题.总体来说,随着回水流量的增加,颗粒堆积量减少,上升管束中的固含率增加,颗粒分布的不均匀度减小,颗粒分布得更加均匀.随着颗粒加入量的增加,上升管束中的固含率增大,颗粒分布不均匀度大致呈现出波动的趋势.随着颗粒粒径的增大,锅炉上升管束中的固含率则呈现出先增大、后减小的趋势,颗粒分布的不均匀度增大.水冷壁管和八字烟道管中的平均固含率相近,这有利于强化传热和防、除垢;而冲刷管中的固含率则明显高于水冷壁管和八字烟道管.构建了三维图来综合反映操作参数对锅炉上升管束中颗粒分布不均匀度的影响,用以指导工业实践.研究的结果有助于促进流化床换热防垢节能技术在锅炉中的应用.
Based on the combination of the fluidized bed heat-transfer and fouling prevention technology with the boiler,a cold-model circulating fluidized bed boiler was designed and built to prevent fouling and enhance heat transfer.Particle fluidization and distribution were investigated via a visualization study with a charge-coupled device(CCD).Polyformaldehyde(POM)particles with different sizes were selected as the inert solid particles.The effects of operating parameters such as the feedwater flow rate,number of added particles,and particle size were systematically investigated.The results showed that the solid particles could be normally circulated in the boiler and well distributed in the riser tube bundle under suitable operating conditions.However,particle accumulation also existed in the drum.With the increase in the feedwater flow rate,the particle accumulation decreased and the solid holdup increased in the riser tube bundle.The nonuniform degree of particle distribution decreased and the particle distribution became even.With the increase in the number of added particles,the solid holdup in the riser tube bundle increased,but the nonuniform degree fluctuated.With the increase in particle size,the nonuniform degree increased,but the solid holdup initially increased and then decreased.The average solid holdups of the water wall tube and the splayed flue tube were close,which is beneficial to heat transfer enhancement and fouling prevention.The solid holdup in the flush tube was significantly higher than those in the water wall tube and the splayed flue tube.Three-dimensional diagrams were constructed to present the effects of the operating parameters on the nonuniform degree in the riser tubebundle. The findings are beneficial to the industrial application of the fluidized bed heat-transfer and fouling preventiontechnology for boilers.
作者
姜峰
沈宇
齐国鹏
景文玥
李修伦
Jiang Feng;Shen Yu;Qi Guopeng;Jing Wenyue;Li Xiulun(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China;School of Biological and Environmental Engineering,Tianjin Vocational Institute,Tianjin 300410,China)
出处
《天津大学学报（自然科学与工程技术版）》
EI
CAS
CSCD
北大核心
2021年第6期607-616,共10页
Journal of Tianjin University：Science and Technology
基金
化学工程国家重点实验室开放项目(SKL-ChE-18B03).
关键词
颗粒分布
循环流化床锅炉
可视化
强化传热
防、除垢
particle distribution
circulating fluidized bed boiler
visualization
heat-transfer enhancement
fouling prevention
