链箅机铁矿球团料层催化脱硝的反应行为及影响因素  

Reaction behavior and influencing factors of catalytic denitration of iron ore pellets in chain grate

作　　者：甘敏[1] 朱亮 范晓慧[1] 季志云[1] 孙增青 郑浩翔 GAN Min;ZHU Liang;FAN Xiao-hui;JI Zhi-yun;SUN Zeng-qing;ZHENG Hao-xiang(School of Mineral Processing and Bioengineering,Central South University,Changsha 410083,Hunan,China)

机构地区：[1]中南大学资源加工与生物工程学院,湖南长沙410083

出　　处：《钢铁》2021年第12期36-42,61,共8页Iron and Steel

基　　金：国家自然科学基金资助项目(51974371)。

摘　　要：在资源约束、环保压力趋紧的形势下,新时期球团环保的重点是减少NO_(x)的排放,其高效控制关系着球团行业的生存。以铁矿球团为对象,研究了球团料层温度对不同铁精矿球团脱硝的影响,在此基础上研究了链箅机抽风干燥段(DDD段)催化脱硝的反应行为,并通过脱硝率、氨利用率等来表征烟气成分对DDD段喷氨脱硝的影响。研究结果表明,在相同条件下,赤铁精矿的催化性能优于磁铁精矿和混合铁精矿,同时分析了链箅机各段温度分布的特点,最终选择DDD段作为SCR脱硝的反应区域。DDD段适宜的脱硝条件为,温度为300~350℃,氧气体积分数为15%~20%,氨氮比(物质的量比)为0.5;在链箅机抽风干燥段进行SCR脱硝时,烟气中的SO_(2)体积分数由0提高到0.050%,反应脱硝率由51.0%降低到34.4%;随着烟气中水蒸气含量的提高,反应脱硝率降低,在水蒸气体积分数为9%时,脱硝率仅为44.9%,总体来讲,控制SO_(2)体积分数小于0.040%,水蒸气体积分数小于6%,可以获得40%左右的脱硝率,在DDD段喷氨催化法脱硝是高效可行的。Under the situation of resource constraint and environmental protection pressure,in the new period,the key point of pelletizing environmental protection is to reduce NO_(x) emission,and its efficient control is related to the survival of pelletizing industry.Taking iron ore pellets as the object,the effect of temperature on denitrification of different iron concentrate pellets was studied.On this basis,the catalytic denitrification reaction behavior of the down-draft drying section(DDD section) of the grating machine was studied and the influence rule of flue gas composition on denitrification in DDD section was characterized by denitrification rate and ammonia utilization,etc.The results show that the catalytic performance of hematite is better than that of magnetite and mixed ore,at the same time,the characteristics of the temperature distribution in each section of the grate machine are analyzed,and the DDD section is finally selected as the reaction zone for SCR denitration.and the optimum denitration conditions are as follows,temperature is 300-350 ℃;the volume percent of oxygen is 15%-20%,the molar ratio ammonia to nitrogen is 0.5;when SCR denitrification is carried out in the grate down-draft drying section,the volume percent of SO_(2) in the flue gas is increased from 0 to 0.050%,and the reaction denitrification rate is reduced from 51.0% to 34.4%;with the increase of the water vapor(volume percent) in the flue gas,the reaction denitration rate decreases,when the water vapor(volume percent) is 9%,the denitration rate is only 44.9%.Generally speaking,the denitrification rate of about 40% can be obtained by controlling volume percent of SO_(2) 0.040% and the water vapor(volume percent) is less than 6%.The denitration rate is highly effective and feasible in the DDD section of the ammonia spray catalytic denitration method.

关 键 词：铁矿球团 链箅机 抽风干燥段 喷氨脱硝 NO_(x)减排 

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