煤种对超细煤粉再燃脱硝效率影响的数值研究  

A Numerical Study of the Influence of Coal Ranks on Reburning-based Denitration Efficiency of Superfine Pulverized Coal

作　　者：贾艳艳[1] 毕明树[1] 柳智[1] 

机构地区：[1]大连理工大学化工学院,辽宁大连116012

出　　处：《热能动力工程》2007年第5期542-547,共6页Journal of Engineering for Thermal Energy and Power

摘　　要：应用CFD计算软件FLUENT6.1,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5种煤质差异较大的超细煤粉作为再燃燃料,研究其NOx排放随再燃区长度、再燃燃料投射位置、再燃区过量空气系数及再燃量的变化规律。结果表明,对于不同煤种的再燃燃料,再燃燃料投射位置存在同一最佳值;煤种挥发分越大,再燃效果越显著;NOx的脱除率随着再燃区长度的增加而增大,随着再燃量的提高亦增大。再燃区过量空气系数对NOx脱除率有重要影响,通过分析计算结果,得到了描述再燃煤粉干燥基挥发分含量Vd和再燃区过量空气系数最佳值αop关系的经验公式,为燃烧参数的优化提供了便利的途径。By using CFD(computational fluid dynamics) calculation software FLUENT6.1 a three-dimensional numerical simulation was performed of the superfine pulverized-coal reburning process in a full-size tangentially fired boiler.With five kinds of superfine pulverized coal having a comparatively big difference in coal quality serving as the reburning fuels,studied was the law governing the variation of NOx emissions with the following factors:the length of the reburning zone,injection location of the reburning fuel,excess air ratio α op in the reburning zone and reburning quantity.The study results show that for different coal ranks serving as reburning fuels there exists an identical optimal injection location of a reburning fuel.The greater the coal volatile content,the more notable the reburning effectiveness.The NOx removal rate increases with an increase of the length of the reburning zone and the reburning coal quantity.The excess air ratio in the reburning zone has a major influence on the NOx removal rate.Through an analysis of the calculation results,an empirical formula was obtained,showing the relationship between the volatile content Vd of the dry fuel basis of the reburning pulverized coal and the optimal value of excess air ratio α op in the reburning zone,thus providing a convenient approach for the optimization of combustion parameters.

关 键 词：超细煤粉 再燃脱硝 数值模拟 全尺寸锅炉 

分 类 号：TK229.6[动力工程及工程热物理—动力机械及工程]