煤粉浓淡空气分级燃烧过程的数值模拟  

Numerical Simulation on Processes of Pulverized Coal Bias Air-staged Combustion

作　　者：毕明树[1] 张丛[1] 周一卉[1] 

机构地区：[1]大连理工大学化工机械学院,大连116012

出　　处：《动力工程学报》2010年第8期612-616,共5页Journal of Chinese Society of Power Engineering

基　　金：国家自然科学基金资助项目(50076006)

摘　　要：采用Fluent 6.3软件,对1台400 t/h四角切圆燃煤锅炉内的煤粉浓淡、空气分级及两者联用等3种燃烧过程进行了数值模拟,分析了煤粉浓淡比对炉内NOx和煤烟生成的影响.结果表明：与原始工况相比,仅采用煤粉浓淡燃烧时,NOx的生成量降低12.6%,但煤烟生成量会增加.当联合使用煤粉浓淡与空气分级燃烧时,随着煤粉浓淡比的增大,NOx生成量逐渐减少,当浓淡比值大于5时,NOx生成量的降低幅度趋于平缓;煤烟生成量随着煤粉浓淡比的增大先减少后增加,当煤粉浓淡比为3~5时,煤烟生成量最少.在两者联用条件下,NOx生成量的降幅可达27.6%,同时煤烟生成量也有所下降,这对锅炉的优化改造有一定的指导作用.Taking a 400 t/h tangentially fired boiler as an example,numerical simulation was carried out to the combustion process respectively at the coal bias, air-staged and combined coal bias air-staged three modes using Fluent 6.3 software, so as to analyse the influence of the coal rich/lean ratio on emission of NO_x and soot.Results show that compared with the original working condition,12.6% NO_x emission is reduced at the coal bias combustion mode,while more soot produced;whereas at the combined mode of coal bias air-staged combustion,NO_x emission first reduces with growing rich/lean ratio,then becomes relatively stable when the rich/lean ratio gets above 5.Simultaneously,soot emission first rises,then reduces with growing rich/lean ratio,and the minimum ash emission occurs at the ratio of 3-5.At the combined mode,NO_x emission can be reduced up to 27.6%,while the soot emission also reduced.This may serve as a reference for future retrofit of boilers.

关 键 词：燃煤锅炉 四角切圆燃烧 煤粉浓淡比 空气分级燃烧 NOX排放量 煤烟排放量 数值模拟 

分 类 号：TK224.1[动力工程及工程热物理—动力机械及工程]