固定污染源烟气汞排放在线连续监测中的若干难点及系统设计

Mercury continuos emission monitoring:The difficulties and system design

我国是一个产煤大国,而且由于我国燃煤技术普遍落后,燃煤释放的汞对环境生态系统的污染更为严重,因此对烟气重金属汞的排放监测是很重要的。烟气汞排放的的测量主要有湿化学分析法、干法吸附剂法和在线分析法。由于汞的特殊性及烟气中汞形态的复杂性,烟气汞在线连续监测有较多的难点。本文在介绍汞的危害、当前汞监测的主要方法的基础上,提出了若干个烟气汞在线监测的难点,比如浓度低、易吸附、汞形态转换、抗干扰等,并针对这些难点提出了一定的解决方案,最后设计了一套烟气汞排放在线监测系统,主要包括烟气采样、样气传输、气体转化、冷凝除湿、汞分析仪、流量控制等单元,并对其性能进行了相关测试。

In this paper, some difficulties on mercury measurement of online monitoring system are put forward such as low concentration, absorbed easily by other materials, mercury speciation transformation, and the solutions are given to these problems. The mercury continuous emission monitoring system have be de- signed including sample gas probe, gas transportation part, mercury converting component, cooling system, mercury analyzer and flow controlling component. Some test results of the system are showned in this paper.