水泥炉窑中低温催化脱硝技术中试性能

利用中低温SCR脱硝技术路线对水泥窑炉进行深度脱硝，设计建设了烟气处理量为10000m³/h的SCR中试实验装置，考察了在SNCR装置后烟气中未能反应的NH₃进一步在SCR（selective catalytic reduction）装置的脱硝效果，并分析了不同入口NO_x浓度对脱硝率的影响.结果表明，所研究的水泥厂仅采用SNCR（selective non-catalytic reduction）和低氮燃烧技术，能够将烟气中的NO_x控制在100~135mg/Nm³，在不喷氨的状态下SCR系统的脱硝效率可达到50%以上，说明SNCR反应存在着一定懂得氨逃逸；在SCR系统补充喷射氨气后，SCR脱硝效率有显著的提升，可提到至80%以上.通过低氮燃烧、SNCR与SCR等脱硝技术的联合使用，可将水泥炉窑烟气中NO_x的排放浓度控制在50mg/Nm³以内，满足超低排放要求；将经过较长时间稳定运行后催化剂从系统中取出，进行成分、孔径分布和脱硝活性对比，结果表明催化剂内部微孔会被部分堵塞，导致比表面积降低，但经吹扫处理催化剂的脱硝效率可恢复，说明催化剂在水泥窑炉烟气条件下长期运行未出现中毒现象.

A pilot scale study of low-temperature De-NOx in cement furnace

Low temperature selective catalytic reduction (SCR) combined with low-nitrogen combustion and selective non-catalytic reduction (SNCR) were used for deep De-NO_x in a cement kiln. The SCR pilot plant with a flue gas of 10000m³/h was designed and constructed. The De-NO_x effect of SCR using residual NH₃ after SNCR was investigated, and the influence of inlet NO_x concentration on the catalytic efficiency was also studied. To meet the emission standard, the SNCR and low-NO_x burner techniques were carried out and the concentration NO_x in flue gas was 100~135mg/m³. The De-NO_x efficiency of SCR could reach more than 50% without the ammonia injection, which indicated the existence of NH₃ slip of SNCR. With the increase of ammonia injection quantity, the De-NO_x efficiency of SCR can be significantly improved. After a long time of test, the proposed De-NO_x technology scheme could stably and effectively control the NO_x emission in flue gas, and could meet the ultra-low emission standard. Finally, the influence of dust on the micropore blockage of catalyst was investigated, which indicated that the soot blowing system of catalyst was very important to guarantee the performance of catalyst.