摘要
为解决负荷变化直接影响脱硝系统入口烟气流场,导致喷氨匹配较差,造成脱硝系统出口氨逃逸率升高而引起空气预热器堵灰等问题,对某电厂600 MW机组选择性催化还原(SCR)装置,在600MW负荷下进行了现场喷氨优化调整试验,并基于流场多变,对现场优化调整试验后的效果,在320MW工况下进行了验证试验。结果表明:喷氨优化后,反应器A、B出口的NO_x质量浓度分布均匀性均有明显提高,其相对标准偏差分别由27.8%、20.2%降低到16.2%、14.6%;在脱硝效率和氨氮摩尔比变化幅度不大的情况下,反应器A、B两侧的平均氨逃逸率分别下降了63.6%和64.3%,优化效果显著;320 MW负荷下SCR反应器出口NO_x质量浓度分布仍然不均匀,其相对标准偏差增大,且在氨氮摩尔比一定时其脱硝效率低于600 MW工况,与理论方法分析的结果相比实际测试脱硝效率值偏低。建议改进或优化脱硝系统进口烟道的整流装置实现流场均匀,以改善脱硝系统出口NO_x分布的均匀性,降低氨逃逸率,同时提高脱硝效率。
The varying load directly affects flue gas flow field distribution at denitration reactor inlet, this negative effect raises the amount of ammonia escape and makes air preheater be blocked. To solve this problem,field ammonia-injection optimization experiments were conducted on the SCR device of a 600 MW unit in a power plant,and the parallel experiment at 320 MW load was performed to verify the optimization effect. The results show that, after the field ammonia-injected optimization, the distribution uniformity of NOx volume fraction at the inlet and outlet of both reactor A and B was dramatically improved,where the relative standard deviation reduced respectively from 27.8% to 16.2% and 20.2% to 14.6%. The average ammonia escape concentration on both sides of the reactor reduced by 63.6% and 64.3% respectively un- der conditions with slight change of denitration efficiency and NH3/NO ratio, which indicates an obvious optimization effect. However, in the parallel experiment, it was observed that the uneven distribution of NOx concentration at the SCR reactor outlet was still not be fairly improved gthe relative standard deviation Uk increased,and the denitration efficiency was lower than that under 600 MW when the NH3/NO ratio stayed constant. Compared with the theoretical analysis, the denitration efficiency measured at field test was relatively low. It was suggested that the rectifier device at the denitration system inlet flue be opti- mized to realize uniform flow field,thus to improve the NOx distribution uniformity at the denitration sys- tem outlet,reduce the ammonia escaping rate,and increase the denitration efficiency.
作者
成明涛
钟俊
廖永进
范军辉
高正阳
CHENG Mingtao ZHONG Jun LIAO Yongjin FAN Junhui GAO Zhengyang(Electric Power Science Research Institute of Guangdong Power Grid Co. , Ltd. , Guangzhou 510080, China School of Energy and Power Engineering, North China Electric Power University, Baoding 071003,China)
出处
《热力发电》
CAS
北大核心
2016年第12期130-136,共7页
Thermal Power Generation
基金
南方电网科研项目(K-GD2014-173)
关键词
烟气脱硝
负荷变化
SCR
喷氨优化
氨逃逸
流场不均匀
脱硝效率
flue gas de-NOx, load change, SCR, ammonia injected optimization, ammonia escape, uneven flow field, denitration efficiency
