新型短流程SCR烟气脱硝系统的模拟分析及优化  

Simulation analysis and optimization of new short process SCR flue gas denitration system

作　　者：陈笛 常庆明[1] 王泽政 CHEN Di;CHANG Qingming;WANG Zezheng(Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China)

机构地区：[1]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081

出　　处：《天然气化工—C1化学与化工》2022年第3期118-124,共7页Natural Gas Chemical Industry

基　　金：国家自然科学基金(51375353)。

摘　　要：以新型短流程选择性催化还原(SCR)烟气脱硝系统为研究对象,通过模拟计算了系统内催化剂层入口截面(截面B)上烟气速度和NH;与NO浓度比的分布。分析了导流板布置对烟道流场分布均匀性的影响,以及喷氨格栅喷嘴的布置、数量和直径对截面B上NH;与NO浓度比均匀性的影响。结果表明:无导流板时,截面B上烟气速度相对标准偏差为27.00%,速度分布不均;沿Z方向均匀布置12块导流板、沿X方向均匀布置6块导流板后,能消除变截面引起的烟气低速回流现象,此时截面B上烟气速度相对标准偏差为13.60%,烟气速度均匀性提高。保持喷氨量不变,喷嘴直径为35 mm,增加喷嘴数量有利于提高截面B上NH;与NO浓度比分布的均匀性,进而提高脱硝效率,但会增加加工成本。增加喷嘴直径,截面B上NH;与NO浓度比相对标准偏差先减小后增大,最佳喷嘴直径为35 mm。优化后,截面B上NH;与NO浓度比相对标准偏差为4.56%,满足工程要求。Taking the new short process selective catalytic reduction(SCR) flue gas denitration system as the research object, the distribution of flue gas velocity and NH;and NO concentration ratio on the inlet section(Section B) of catalyst layer in the system was simulated. The influence of deflector arrangement on the uniformity of flue flow field was analyzed, and the influence of nozzle arrangement, number and diameter on the uniformity of NH;and NO concentration ratio on Section B was studied. The results show that without deflector, the relative standard deviation of flue gas velocity on Section B is 27%, and the distribution of flue gas velocity is uneven. By evenly arranging 12 deflectors along the Z direction and 6 deflectors along the X direction, the phenomenon of flue gas low-speed reflux caused by variable section can be eliminated, and the relative standard deviation of velocity on Section B is reduced to 13.6%, and the flue gas velocity uniformity on Section B is improved. When the ammonia injection amount remains unchanged and the nozzle diameter is set to 35 mm, increasing the number of nozzles is conducive to improve the uniformity of NH;and NO concentration ratio distribution on Section B and thus improve the denitration efficiency, but it will increase the processing cost.With the increase of nozzle diameter, the relative standard deviation of NH;and NO concentration ratio on Section B first decreases and then increases, and the optimal nozzle diameter is 35 mm. After optimization, the relative standard deviation of NH;and NO concentration ratio on Section B is 4.56%, which meets the engineering requirements.

关 键 词：烟气脱硝 导流装置 喷氨格栅 数值模拟 

分 类 号：X701[环境科学与工程—环境工程]