煤粉粒度对超细煤粉再燃脱硝效率影响的数值模拟  

Numerical simulation of effect of coal particle size on NO_x reduction in micro-pulverized coal reburning

作　　者：贾艳艳[1] 毕明树[1] 柳智[2] 

机构地区：[1]大连理工大学化工学院,辽宁大连116012 [2]中冶赛迪工程技术股份有限公司动力设计部,重庆400013

出　　处：《煤炭学报》2008年第11期1296-1300,共5页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(50076006)

摘　　要：借助CFD计算软件Fluent 6.1,对全尺寸四角切圆锅炉超细煤粉再燃烧过程进行了三维数值模拟.以烟煤的超细煤粉作为再燃燃料,研究了NOx排放随再燃煤粉粒径、再燃区过量空气系数及再燃量的变化规律,并给出了不同再燃煤粉粒径工况下炉膛中心截面上NOx浓度分布.结果表明,对于不同粒度的再燃燃料,再燃区过量空气系数存在同一最佳值,在0.8-0.9之间;脱氮率随着再燃量的增加而增大,最佳再燃量为20%;再燃煤粉越细,对NOx的还原作用越强,最佳再燃燃料平均粒径为20μm.Three dimensional numerical simulation of micro-pulverized coal reburning process in full-scale tangentially fire boiler was conducted with CFD software Fluent 6. 1. Bituminous coal was chosen as reburning fuel to study the effects of micro-pulverized coal size, stoichiometric ratio in rich zone and reburning fuel fraction on NOx emissions. NOx concentration field with different particle sizes of reburning coal were given. The results indicate that when the stoichiometric ratio is between 0. 8 -0.9 in rich zone, the NOx reduction efficiency reaches the largest value for different particle sizes of reburning fuel; the larger reburning fuel fraction is, the higher NOx reduction efficiency is ; the optimum reburning fuel fraction is 20% ; NOx reduction efficiency increases with the decrease of particle size of reburning fuel. The optimum particle size of reburning fuel is 20 μm.

关 键 词：超细煤粉 再燃脱硝 数值模拟 全尺寸锅炉 

分 类 号：TQ534[化学工程—煤化学工程]