燃煤锅炉SCR脱硝过程对颗粒物和痕量元素的影响

发布时间：2018-06-06 17:32

本文选题：煤粉锅炉 + SCR　；参考：《煤炭学报》2015年11期

【摘要】：选择性催化还原(SCR)技术广泛被应用于燃煤电厂NOx减排,而SCR脱硝技术对颗粒物(PM)的影响尚不清楚。在两台300 MW煤粉锅炉机组SCR反应器的入口和出口进行了颗粒物现场采样,分析了SCR脱硝过程对PM的质量粒径分布和痕量元素含量的影响。研究结果显示,SCR脱硝过程产生NH+4,SO2+4等组分并部分转化为颗粒物,促使0.1μm以下颗粒物团聚、长大,导致0.3μm以下颗粒物的峰值粒径由0.1μm增大到0.3μm,同时使S含量显著升高,最终导致0.3μm以下颗粒物浓度升高约30.67%。烟气中部分0.3μm以上颗粒物在SCR反应器中受惯性碰撞作用而分离,使其浓度降低0.06%~33.11%,但峰值粒径和组成成分不变。SCR反应器入口烟气中的气态痕量元素在脱硝过程中向颗粒物转移,引起PM中痕量元素含量变化。实验条件下,经过SCR反应器后,0.3μm以下颗粒物中Cd,As,Pb含量分别升高104.15%,12.26%和12.18%,而Cr含量降低23.38%;0.3μm以上颗粒物中各痕量元素含量均略有升高。
[Abstract]:Selective catalytic reduction (SCR) technology is widely used to reduce NOx emissions in coal-fired power plants, but the effect of SCR on particulate matter (PMN) is not clear. Particle sampling was carried out at the inlet and outlet of SCR reactor of two 300 MW pulverized coal boiler units. The effect of SCR denitrification process on mass particle size distribution and trace element content of PM was analyzed. The results showed that NH _ 4O _ 2 _ 4 and other components were partially converted into particles during SCR denitrification, which promoted the agglomeration of particles below 0.1 渭 m and grew up, resulting in the increase of the peak particle size from 0.1 渭 m to 0.3 渭 m, and the significant increase of S content. The concentration of particulate matter below 0.3 渭 m was increased by 30.67%. Some particulate matter above 0.3 渭 m in flue gas was separated by inertial collision in SCR reactor, which reduced its concentration by 0.06% and 33.11%, but the peak particle size and composition were not changed. The trace gaseous elements in flue gas from the inlet of SCR reactor were transferred to particulate matter during denitrification. The content of trace elements in PM was changed. Under the conditions of SCR reactor, the content of CD ~ (2 +) As-Pb in particles below 0.3 渭 m increased by 12.26% and 12.18%, respectively, while the content of Cr decreased by 23.38 渭 m, and the contents of trace elements in particles above 0.3 渭 m increased slightly.
【作者单位】：广东电网有限责任公司电力科学研究院;华中科技大学煤燃烧国家重点实验室;
【基金】：国家自然科学基金资助项目(51476064) 煤炭联合基金资助项目(U1261204) 国家重点基础研究发展计划(973)资助项目(2013CB228501)
【分类号】：X773

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