【作者】 侯祥松； 张海； 李金晶； 吕俊复； 岳光溪；

【Author】 Hou Xiangsong,Zhang Hai, Li Jinjing, Lu Junfu,Yue Guangxi Department of Thermal Engineering, Tsinghua University, Beijing 100084

【机构】 清华大学热能工程系；

【摘要】 选择性非催化还原(SNCR)是一种使用广泛的烟气脱硝技术,本文介绍了SCNR的反应机理,总结分析了目前在世界各地运行的SNCR装置的运行情况和多种锅炉参数和操作条件对SCNR脱硝效率的影响。SNCR通常采用氨水或者尿素作为还原剂,由于各自的运行条件不同,其NOx脱除率处于38~82%的范围内。在运行中,SNCR装置的NOx脱除率主要受到还原剂种类、燃料种类、锅炉类型和锅炉容量等因素的影响。本文利用固定床反应器研究了不同的燃料种类对SNCR过程的影响,研究表明,煤灰对SNCR过程有催化作用,其中的CaO、Fe2O3等成分是催化反应有效的活性成分。还原剂与烟气的混和情况也是影响脱硝效率的重要因素,也是在大型电站锅炉中采用SNCR脱硝的技术瓶颈,本文计算研究了混和情况的影响。本文综合比较了影响SNCR反应效率的主要因素,在循环流化床锅炉中,由于温度分布合理,且有高浓度的循环灰作为催化剂,气体的混和情况好,适合采用SNCR脱硝技术。更多还原

【Abstract】 Selective Non-Catalytic(SNCR) is one of the popular low-NOx technique all over the world. In this paper, the mechanisms of SCNR are introduced and the practices of SCNR over the world are summarized. Shown by statistic data, using ammonia or urea for reducing agent, the NOx removal efficiency on various boilers ranges in 38-82%. The effects of some boiler parameters and operation conditions on the NOx removal efficiency for the SCNR are discussed. It is found that SCNR efficiency is influenced by the types of reducing agents, fuel, boiler type, boiler capacity and the injection and mixing of reducing agents. In this paper, the influence of different fuel is approached in a fixed bed reactor. Coal ash plays as catalytic during SNCR, especially the CaO and Fe2O3 are active catalytic for NOx’s deprivation. The mixing of reducing agent and NOx is very important too, it is the bottleneck for SNCR especially for some large-sized boilers. Calculation is carried out for the mixing condition in large-sized boilers. In circle fluidized bed(CFB) boilers, its temperature is fit for SNCR reactions while the dense circle ash plays as catalytic, the mixing of fume and reducing agent is promoted by circle ash too, so it is reasonable that SNCR is much more effective is CFB boilers.更多还原