摘要
相对于高温高尘区SCR脱硝工艺,高温低尘布置的SCR工艺在保护催化剂和空气预热器方面具有明显优势。因此提出了一种高温除尘脱硝一体化技术,将高温电袋复合除尘器和SCR脱硝反应器有机结合,对比分析了下进上出、侧进侧出和上进下出3种脱硝反应器形式,下进上出布置形式以其结构简单、经济性高等优点成为优选结构形式。以某350 MW机组为对象,采用Fluent软件对其高温除尘脱硝一体化装置开展了数值模拟研究,分析了装置内的流场分布情况,并提出了优化设计方案。结果表明,通过改进烟道结构和设计导流措施(烟道导流板、整流格栅、孔板开孔率、灰斗阻流板等)减小了烟道内涡流、改善了装置内的流场分布。优化后,喷氨入口、第一电场入口、首层催化剂入口和空预器入口的速度分布变异系数由优化前的27.1%、38.8%、17.6%、22.4%降低为12.1%、22.3%、5.5%、11.3%,首层催化剂入口的氨浓度分布变异系数和入射烟气角度由优化前的15.0%、172°降低为3.8%、5.3°,满足相关的流场技术要求,为工程设计提供可靠的指导依据。
Compared with the SCR-DeNOx system of high temperature and high dust area arrangement,the arrangement of high temperature and low dust area has obvious advantages in protecting catalyst and air preheater.An integrated technology of high temperature dedusting and denitrification was proposed,which combined high temperature electric bag composite dust collector and SCR denitrification reactor.Three types of flow in and out of the denitrification reactor,including lower flow in and upper flow out,side flow in and side flow out,upper flow in and lower flow out were compared and analyzed.The results show that the first type has the advantages of simple structure and high economy.At the same time,,using a 350 MW unit as an example,the numerical simulation of high temperature dedusting and SCR-DeNOx integrated device was carried out by using Fluent software.The flow field distribution inside the device was analyzed,and the optimized design scheme was proposed.The simulation results show that the flow field distribution in device can be improved and the vortex in the flue can be reduced by improving flue structure and design diversion measures(flue deflector,rectifier grille,adjusting orifice opening rate,ash-bucket baffle,etc.).After optimization,the velocity distribution variation coefficient at inlet section of AIG,the first electric field,the 1st catalyst and air preheater are decreased from 27.1%,12.1%,38.8%,17.6% before optimization to 22.4%,22.3%,5.5%,11.3%,respectively.And,the ammonia concentration distribution variation coefficient and the flue gas incidence angle at inlet section of the 1st catalyst are reduced from 15.0% and 172°before optimization to 3.8%and 5.3°,respectively,so as to meet relevant technical requirements of flow field,and provide reliable guidance for engineering design.
作者
王为
朱召平
张楚城
陈牧
苏寅彪
郑晓盼
WANG Wei;ZHU Zhaoping;ZHANG Chucheng;CHEN Mu;SU Yinbiao;ZHENG Xiaopan(Central Southern Electric Power Design Institute,Wuhan 430000,China;Fujian Longking Co.,Ltd.,Longyan 364000,China)
出处
《洁净煤技术》
CAS
2020年第4期154-161,共8页
Clean Coal Technology
基金
福建省科技重大专项资助项目(2018YZ0003)。
关键词
除尘脱硝一体化
高温低尘SCR布置
数值模拟
流场优化
integration of dedusting and denitration
SCR arrangement in high temperature and low dust area
numerical simulation
flow field optimization
