关于烟气在线监测装置SO_2周期性异常的分析与处理

Analysis and Treatment on the Cyclical Abnormal of SO_2 Data of Flue Gas Online Monitoring Device

本文针对目前电厂脱硫烟气连续排放监测系统(CEMS)中SO2数据周期性波动,通过对历史数据曲线分析排查,发现取样探头温控仪故障导致取样探头加热器无法加热,烟气中水分遇冷凝结在管壁,管壁中的水分平时吸收烟气中的SO2,导致测量值偏低,待水珠汇聚变大流入下面带加热的取样管中后,水中溶解SO2的集中释放,导致数据在短期急剧上升,蒸发释放完后回归到原来的水平,形成这样一个周期性吸收和集中释放的过程。可见烟气取样管道温度保护环节在烟气测量中的作用非常重要。

This paper aims at analyzing the cyclical fluctuations of the SO2 data in flue gas desulfurization Continuous Emission Monitoring System （CEMS） in the current power plant. By thoroughly investigating the historical data, authors find that the fault of sampling probe temperature controller may lead to the hearing failure of sampling probe heater, so that water vapor in flue gas, which normally absorbs SO2, condenses in the wall, which results in the low measured value. When the water in the wall grows larger and larger, and becomes the small currents, it will go to the following tube with heating. Meanwhile, the SO, dissolved in the water is released, which results in data sharp rise in the short term. The data will return the original level after SO2 is released, which forms a cyclical process of uptake and concentration. Therrcforc, protection of flue gas sampling tubes plays a very important role in temperature measurement.