电厂飞灰对SO_(2)电化学传感器测量准确度的影响  

Effect of fly ash on measurement accuracy of SO_(2) electrochemical sensor in thermal power plant

作　　者：张邯平 米康民[2] 阎寒冰 陈秀芳 张振宇 柳逢春 ZHANG Hanping;MI Kangmin;YAN Hanbing;CHEN Xiufang;ZHANG Zhenyu;LIU Fengchun(Institute of Electric Power Research of State Grid Shanxi Electric Power Company,Taiyuan 030299,China;State Grid Shanxi Electric Power Company,Taiyuan 030001,China)

机构地区：[1]国网山西省电力公司电力科学研究院,山西太原030299 [2]国网山西省电力公司,山西太原030001

出　　处：《热力发电》2022年第12期119-125,共7页Thermal Power Generation

基　　金：国网山西省电力公司科技项目(52053020002R)。

摘　　要：针对监测火电厂周围空气污染物时,SO_(2)电化学气体传感器出现测量不准和使用寿命较短等问题,以山西省朔州市某煤矸石发电厂飞灰为研究对象,在分析飞灰形貌特征的基础上,通过理论计算得到飞灰沉降速度和不同时间沉积量,通过实验测试飞灰对SO_(2)传感器测量误差的影响。研究结果表明:飞灰直径分布范围4~10μm,飞灰沉降速度2.25×10^(-3) m/s,1天沉积量为1.55 mg;飞灰沉积时间会影响传感器测量误差,沉积时间越长,传感器中气体扩散面积s和扩散系数K减小,传感器测量误差越大;飞灰沉积条件下气体质量浓度越大,气体到达工作电极区域速度越快,在有限响应时间内检测到的有效SO_(2)质量浓度越高,传感器测量误差越小;在飞灰较多环境下使用SO_(2)电化学传感器时,建议加装孔径小于4μm透气滤膜防尘并定期清理沉积飞灰。Aiming at solving the problems of inaccurate measurement and short service life of SO2electrochemical gas sensor in monitoring air pollutants around thermal power plants, by taking the fly ash from a gangue-fired power plant in Shuozhou, Shanxi Province as the research object, and based on the analysis of the morphological characteristics of fly ash, the settling speed of fly ash and the amount of deposition at different times were obtained through theoretical calculation, and the influence of fly ash on the measurement error of SO_(2) sensor was tested by experiments. The results show that, the diameter distribution range of the fly ash is 4~10 μm, the settling velocity of the fly ash is 2.25×10^(-3) m/s and the deposition amount in one day is 1.55 mg. The deposition time of fly ash will affect the measurement error of the sensor, the longer the deposition time, the greater the measurement deviation of the sensor. The reason is that the deposition of fly ash leads to the reduction of gas diffusion area s and diffusion coefficient K of the electrochemical sensor. Under the condition of fly ash deposition, the greater the gas mass concentration, the faster the gas reaches the working electrode area, the higher the effective SO_(2) concentration detected in the limited response time, and the smaller the measurement error of the sensor. When the SO_(2) electrochemical sensor is used in the environment with a large amount of fly ash, it is recommended to install a filter membrane with pore diameter less than 4 μm to prevent dust and clean the deposited fly ash regularly.

关 键 词：空气污染监测 SO_(2)电化学传感器 沉降速度 火电厂飞灰 形貌扫描 

分 类 号：X831[环境科学与工程—环境工程]