SCR系统出口NO_x均匀性研究及优化方法

Research and Optimization Methods of NO_x Uniformity of SCR System Outlet

以14家电厂SCR系统出口NOx分布情况为例,分析表明,大部分电厂SCR系统出口NOx分布均匀性较差,相对标准偏差远低于20%的可接受范围,且横向偏差大于纵向偏差。分析可知,SCR系统出口NOx分布不均主要由入口NOx分布不均、流场不均、温度场不均、喷氨不均、催化剂催化效果不均及变工况运行等原因引起。另外,SCR系统出口NOx分布不均,将会引起脱硝CEMS数据失真、空预器堵塞与腐蚀加剧和催化剂使用寿命缩短等问题。在此基础上,针对SCR系统出口NOx分布不均的问题,提出了一些优化调整方法及建议。

Taking the NOx distribution situation of SCR system outlet of 14 power plants for example, analysis shows that the uniformity of NOx distribution of SCR system outlet of most power plants is bad whose relative standard deviation is rather lower than the acceptable value 20% and lateral standard deviation is larger than the vertical standard deviation. Due to analysis, the nonuniformity of NOx distribution of SCR system inlet, flow field, temperature field, spray of ammonia, catalytic effect of catalyst and variable working conditions mostly cause the nonuniformity of the NOx distribution of SCR system outlet. The Study shows that the nonuniformity of NOx distribution will cause some harmful effect such as data distortion of CEMS, blocking and corrosion of air preheater and shortage of catalyst life time. Aiming at the problem of the nonuniformity of NOx distribution, relative optimization methods and proposal are raised.