摘要
氨煤混燃是减少燃煤电厂CO_(2)排放的一种可行方法,然而,高NO_(x)排放将是氨煤混燃所面临的主要挑战。为研究NO_(x)控制策略,该文在可灵活控制氨燃烧反应环境的一维氨煤混燃实验炉中对混氨比例(R_(NH3))、燃尽风率和炉膛温度对氨煤混燃NO_(x)生成特性的影响进行实验研究。通过对O_(2)、NO_(x)等组分沿炉膛分布的监测,揭示氨煤混燃炉内的NO_(x)生成过程。结果表明,在NH_3与煤粉预混投入方式下,NO_(x)排放随R_(NH3)增加呈先上升后降低趋势,在混氨比例约为15%时达到最大值;燃尽风率增加使NO_(x)排放显著降低;炉内O_(2)浓度分布对NO_(x)生成起着关键作用,氨煤混燃的NO_(x)生成主要由燃烧初期富氧条件下NO的大量生成和燃烧后期乏氧条件下残余NH_3对NO的还原这两个过程构成。炉膛温度升高促进了煤粉燃烧对O_(2)的消耗,使NH_3燃烧发生在相对乏氧的环境,降低了氨煤混燃的NO_(x)排放。研究结果对全尺寸燃煤锅炉氨煤混燃系统的设计和运行具有一定意义。
Cofiring ammonia(NH_(3))in coal-fired boilers is a promising approach to reduce CO_(2) emissions from thermal power plants.However,high NO_(x) emission is going to be the major challenge faced by of NH_(3)-coal cofiring.To explore the potential NO_(x) control strategies,the effects of NH3 cofiring ratio(R_(NH3)),overfire air(OFA)rates and furnace temperature on the NO_(x) formation characteristics of NH_(3)/coal cofiring are studied in a test furnace designed to allow for flexible control of combustion environment of NH3.By means of monitoring the distributions of key species,such as O_(2) and NO_(x),along the furnace,the NO_(x) formation process of NH_(3) cofiring in the furnace is revealed.The results show that when NH_(3) is injected with coal stream,the NO_(x) emissions tend to increase and then decrease with the increase of R_(NH3),exhibiting peak values at approximately 15% R_(NH3).The NO_(x) emissions decrease with the increase of OFA rates.It is found that the O_(2) distribution in the furnace plays a key role in the formation of NO_(x).The net formation of NO_(x) is governed by the initial NO formation under O_(2)-rich environment during the early stage of combustion and the subsequent reduction of NO by the residue NH_(3) during the later stage of combustion.Increase of furnace temperature tends to promote the O_(2) consumption by coal combustion so that the combustion of NH_(3) takes place in a relatively O_(2)-deficient environment,leading to reduction of NOx emissions.The findings of these paper are instrumental in the design and operation of NH_(3) cofiring system in full scale coal-fired boilers.
作者
谢妍
王耿辉
刘佳宁
李君
刘欣
张文振
张超群
王赫阳
XIE Yan;WANG Genghui;LIU Jianing;LI Jun;LIU Xin;ZHANG Wenzhen;ZHANG Chaoqun;WANG Heyang(School of Mechanical Engineering,Tianjin University,Jinnan District,Tianjin 300350,China;Yantai Longyuan Power Technology Co.,Ltd.,Yantai 264006,Shandong Province,China)
出处
《中国电机工程学报》
北大核心
2025年第2期452-460,I0004,共10页
PROCEEDINGS OF THE CHINESE SOCIETY FOR ELECTRICAL ENGINEERING
关键词
氨煤混燃
NO_(x)
氨逃逸
碳减排
ammonia-coal cofiring
NOx
ammonia slip
reduction of CO_(2)emission
