摘要
电厂烟气脱硝SCR系统脱硝还原剂采用尿素取代液氨已成为行业趋势,尿素具有与液氨相同的脱硝性能,且具有环保、无毒性和安全性高等优点。某电厂对烟气脱硝SCR系统实施液氨改尿素热解制氨工艺,本次改造的热解系统单套640kg/h的制氨量是迄今国内最大的,具有停留时间长、能耗大、运行费用高、调节范围大等难点。为此,在进行流场/温度场模拟的基础上,采用高温烟气换热方案代替电加热器方案,对运行模式和喷枪控制进行了调整。从运行后的数据来看,在锅炉满负荷(600MW)运行时,热解炉系统满足氮氧化物排放低于50mg/m;且氨逃逸低于3μL/L的要求,炉内尿素热解完全,无结晶出现。采用炉内气气管式换热器代替电加热器作为热源,每年可节省电费约570万元,不到半年即可收回投资成本。项目的顺利实施为尿素热解系统的超大型化应用积累了更多经验。
It has become an industry trend to replace liquid ammonia with urea as the denitrification reducing agent in SCR flue gas denitrification system in power plants.With the same denitrification performance as liquid ammonia,urea also has the advantages of environmental protection,non-toxicity and high safety.A power plant modified its SCR flue gas denitrification system from liquid ammonia to urea pyrolysis for ammonia pro-duction.In this modification,the ammonia production capacity of a single pyrolysis system was 640kg/h,the largest in China so far,so there were difficulties such as long residence time,high energy consumption,high operation cost and wide regulation range.Therefore,based on flow field/temperature field simulation,high-temperature flue gas heat exchange scheme was adopted to replace electric heater scheme,and the operation mode and spray injector control were adjusted.According to the operation data after modification,when the boiler is operated at full load(600MW),the pyrolysis system can meet the nitrogen oxide emission requirement of less than 50mg/Nm~3 and the ammonia escape requirement of less than 3μL/L,and the urea in furnace is completely pyrolyzed without crystallization.Using gas-gas tubular heat exchanger in furnace instead of electric heater as the heat source can save the electricity cost by about 5.7million yuan each year,and the investment cost can be recovered in less than half a year.The successful implementation of this project has accumulated more experience for the super large-scale application of urea pyrolysis system.
作者
章新伟
李靖菀
Zhang Xinwei;Li Jingyuan(Shanghai Gehope Environmental Protection Co.,Ltd.,Shanghai 200062)
出处
《中外能源》
CAS
2022年第5期92-95,共4页
Sino-Global Energy
关键词
烟气脱硝
选择性催化还原
脱硝还原剂
尿素
液氨
热解制氨
flue gas denitrification
SCR
denitrification reducing agent
urea
liquid ammonia
urea pyrolysis for ammonia production
