链箅机—回转窑烟气超低排放技术研究与应用  

Research and application of ultra-low emission technology of grate-kiln flue gas

作　　者：刘磊[1] 李斌[1] 张文强[1] 曾琦 LIU Lei;LI Bin;ZHANG Wenqiang;ZENG Qi(Tangshan Iron and Steel Group Co.,Ltd.,Tangshan 063000,Hebei,China)

机构地区：[1]唐山钢铁集团有限责任公司,河北唐山063000

出　　处：《烧结球团》2022年第4期106-112,118,共8页Sintering and Pelletizing

摘　　要：为实现球团烟气超低排放改造,本文通过研究链箅机—回转窑生产工艺,分析烟气中颗粒物、SO_(2)、NO_(x)排放现状,并应用相应超低排放技术措施。结果表明:链箅机预热二段温度为900~1100℃,在脱硝还原剂反应温度区间,采用SNCR工艺改造可降低烟气中NO_(x)约30%左右;臭氧梯级氧化工艺改造,将强氧化剂O_(3)喷入主烟道内使NO氧化成NO_(2),当n(O_(3))/n(NO)(摩尔比)≤1.0时,NO的氧化产物为NO_(2),而随着n(O_(3))/n(NO)>1.0时,在脱硫塔内烟气中部分NO_(2)进一步被氧化为NO_(3),此时NO_(3)与NO_(2)迅速反应生成了N2O5;根据高价态NO_(x)容易被碱性脱硫剂和水吸收的特性,可通过SDA旋转喷雾工艺协同吸收NO_(x)和SO_(2);采用预荷电技术对布袋进行改造后,烟气中粉尘荷电,有利于提高粉尘捕集效率,降低过滤阻力,粉尘排放浓度小于5 mg/m^(3)。In order to realize the ultra-low emission transformation of pelletizing flue gas,based on the research on grate-kiln manufacturing technique,the current status of particulate matter,SO_(2) and NO_(x) emissions in flue gas is analyzed,and the technical measures of corresponding ultra-low emission are applied.The results show that the temperature at the second stage of preheating of the grate is 900~1100℃.The process modification can reduce the NO_(x) in the flue gas by about 30%in the reaction temperature range of denitrification reducing agent;ozone cascade oxidation process transformation sprays the strong oxidant O_(3) into the main flue to oxidize NO to NO_(2),when n(O_(3))/n(NO)(molar ratio)≤1.0,the oxidation product of NO is NO_(2),and with n(O_(3))/n(NO)>1.0,part of the NO_(2) in the flue gas in the desulfurization tower is further oxidized to NO_(3);At this time,NO_(3) and NO_(2) react rapidly to generate N_(2)O_(5);According to the characteristics of high-valence NO_(x) that are easily absorbed by alkaline desulfurizers and water,NO_(x) and SO_(2) can be cooperatively absorbed by the SDA rotary spray process;After the pre-charge technology is used to transform the bag,and the dust charge in the flue gas is conducive to improving the efficiency of dust capture and reducing the filtration resistance,and the dust emission concentration is less than 5 mg/m^(3).

关 键 词：SNCR SDA 臭氧梯级氧化 协同吸收 预荷电 

分 类 号：TF046.6[冶金工程—冶金物理化学] X701[环境科学与工程—环境工程]