HCl对链箅机—回转窑烟气净化系统的影响及其减排措施  

Effect of HCl on chain grate-rotary kiln gas purification system and its emission reduction measures

作　　者：王飞 毛瑞 姚海威 苏航 邵久刚 WANG Fei;MAO Rui;YAO Haiwei;SU Hang;SHAO Jiugang(Research Institute of Iron&Steel of Jiangsu Province(Sha Steel),Zhangjiagang 215625,Jiangsu,China)

机构地区：[1]江苏省(沙钢)钢铁研究院,江苏张家港215625

出　　处：《烧结球团》2024年第6期163-170,共8页Sintering and Pelletizing

摘　　要：链箅机—回转窑烟气中的气体污染物除NO_(x)、SO_(2)外,还含有一定比例的HCl,其对烟气净化系统会造成显著负面影响,影响球团生产作业率。本文通过分析链箅机—回转窑烟气中HCl的生成机理,研究HCl对烟气净化系统的影响,并提出相应改善措施。结果表明:95.85%的氯元素来自各类铁精粉原料,此外,烟气中的HCl在喷氨区与NH_(3)反应生成大量NH 4Cl结晶是导致活性焦硫硝脱除系统运行不畅的主要原因。在实际生产中,可采取的HCl减排措施:减少高氯原料的使用实现源头减排,采用消石灰作为钙质添加剂生产碱性球团抑制HCl的生成,在HCl集中生成的链箅机抽风干燥段喷洒碱液。在喷洒碱液措施下,当n(Na)/n(Cl)(物质的量之比)为2.6时,HCl的脱除率仅为48.7%,其减排效率较低,不能满足生产需要。在添加钙质熔剂措施下,当消石灰配比为1.5%时,原料中氯元素转化为HCl的比例仅有8.2%。在链箅机—回转窑生产线实施SNCR与嵌入式SCR耦合前置脱硝工艺可在HCl生成之前将烟气中NO_(x)脱除,基本隔绝HCl与NH_(3)的接触。对于新建链箅机—回转窑生产线,规划配置前置脱硝系统和活性焦脱硫系统的组合可以避免烟气中HCl的负面影响,实现球团烟气超低排放。In addition to NO_(x) and SO_(2),the gaseous pollutants in the gas of the chain grate-rotary kiln also contain a certain proportion of HCl,which will have a significant negative impact on the gas purification system and affect the pellet production efficiency.The generation mechanism of HCl in the gas of the chain grate-rotary kiln is analyzed,the influence of HCl on the gas purification system is studied,and corresponding improvement measures are proposed.The results show that 95.85%of the chlorine comes from various raw material of iron ore concentrates.In addition,the main reason for the poor operation of the active coke sulfur and denitrification system is that HCl in the gas reacts with NH_(3)in the ammonia injection area to generate a large amount of NH 4Cl crystals.In actual production,the following HCl emission reduction measures can be taken:reducing the use of high-chlorine raw materials to achieve source reduction,using slaked lime as a calcium additive to produce alkaline pellets to inhibit the formation of HCl,and spraying alkaline solution in the exhaust drying section of the chain grate where HCl is concentrated.Under the alkali solution spraying measure,when n(Na)/n(Cl)(the ratio of the amount of substance)is 2.6,the HCl removal rate is only 48.7%,and its emission reduction efficiency is low and cannot meet the production needs.When calcium solvent is added,the proportion of slaked lime is 1.5%,and the conversion rate of chlorine in the raw material into HCl is only 8.2%.The implementation of SNCR and embedded SCR coupled pre-denitrification process in the chain grate-rotary kiln production line can remove NO_(x) from the gas before HCl is generated,basically isolating the contact between HCl and NH_(3).For newly built chain grate-rotary kiln production lines,planning and configuring a combination of a pre-denitrification system and an activated coke desulfurization system can avoid the negative impact of HCl in the gas and achieve ultra-low emissions of pellet gas.

关 键 词：链箅机—回转窑 HCL 活性焦 脱硫 脱硝 

分 类 号：TF046.6[冶金工程—冶金物理化学] X701.7[环境科学与工程—环境工程]