链箅机-回转窑球团NOx超低排放技术研究  

Research on technology of ultra-low NO_x emission from grate-rotary kiln pelletizing process

作　　者：叶恒棣[1,2] 胡兵 魏进超[1,2] Ye Hengdi;Hu Bing;Wei Jinchao(Engineering Technology Center of Sintering&Pelletizing and Direct Reduction,Zhongye Changtian International Engineering Co.,Ltd.,Changsha 410205,Hurmn;National Engineering Technology Research Center of Sintering and Pelletizing Equipment Systemy Changsha 410205,Hunan)

机构地区：[1]中冶长天国际工程有限责任公司烧结球团及直还工程技术中心,湖南长沙410205 [2]国家烧结球团装备系统工程技术研究中心,湖南长沙410205

出　　处：《烧结球团》2020年第1期55-60,76,共7页Sintering and Pelletizing

基　　金：湖南省自然科学基金资助项目(2019JJ51007);长沙市科技重大专项(kq1902003).

摘　　要：基于链箅机-回转窑球团生产过程NOx排放质量浓度高、末端治理投资和运行成本大等问题,在系统分析NOx排放规律和影响因素的基础上,开展了一系列源头控制、过程控制和选择性催化还原脱硝协同处理技术研究。研究结果表明:低NOx燃烧技术、低NOx烧嘴技术、低温焙烧技术是降低球团NOx生成量的有效方法;先进再燃技术是减轻末端治理负荷最直接的技术手段,高NOx烟气脱除效率可超过60%,从而确保了预热二段烟气中NOx质量浓度低于300 mg/m^3;通过有效地抑制预热二段向预热一段串风,并利用烟气的中高温条件,在多管除尘器后增设SCR脱硝系统,不仅无需升温,而且烟气处理量减少50%以上,该阶段烟气含氧量为15%~18%,SCR脱硝效率仅需90%就可以满足球团烟气超低排放的技术指标,与传统末端治理技术相比,节省建设费用1/3、运行费用2/3。In view of the problems of the grate-rotary kiln pelletizing process,such as high NO_x emission concentration in exhaust gas,high cost in investment and operation of terminal treatment,and based on the systematic analysis of the NO_x emission laws and its influencing factors,a series of studies on the collaborative treatment technology of source control,process control and selective catalytic reduction(SCR)for the NO_x emission reduction are carried out.The results show that low NO_x combustion technology,low NO_x burner technology and low temperature roasting technology are the most effective methods to reduce the NO_x generation in pellet production.The advanced reburning technology is the most direct technical means to reduce the end treatment load,and the removal efficiency of NO_x in exhaust gas can exceed 60%,thus ensuring that the NO_x concentration of the exhaust gas in the second preheating zone below 300 mg/m^3.By effectively restraining the movement of gas from the second preheating zone to the first preheating zone,and by taking advantage of the medium and high temperature conditions of the flue gas,the SCR denitrification system is added after the multicyclone deduster,there is no need for raising temperature and the volume of exhaust gas which needs to be treated can be reduced by over 50%.The oxygen content of flue gas reaches 15%~18% in this stage,and the ultra-low emission target can be obtained when the denitrification efficiency of SCR reaches 90%.Compared with the traditional technique of terminal treatment of NO_x,the construction cost and running cost can be saved by 1/3 and 2/3 respectively.

关 键 词：链箅机-回转窑 球团 NOx 超低排放 先进再燃技术 选择性催化还原 

分 类 号：X701[环境科学与工程—环境工程]