内蒙古某电厂逃逸氨浓度测试与灰分影响分析

Ammonia Escape Testing and Ash Impact Analysis for an Inner Mongolia Power Plant

燃煤电厂选择性催化还原(SCR)脱硝系统氨逃逸问题普遍存在,为良好控制逃逸氨浓度,采用靛酚蓝分光光度法在现场对烟气中氨浓度进行了测试。以内蒙古某200 MW级燃煤机组氨逃逸性能试验为例,详述了靛酚蓝分光光度法现场测试的操作方法与流程,并将试验结果与现场在线仪表数据进行了比较,同时分析了烟气中飞灰对该方法测试结果的影响。结果表明,现场测试可获得不同取样点逃逸氨的浓度,对喷氨控制有利;样品中灰分的存在会大幅提升吸光度值,使测试结果偏高,采样过程中需严防灰分进入样品,以便获得正确的分析结果。

The problem of ammonia escape has been existing prevalently in the selective catalytic reduction （SCR） system of coal-fired power plants. In order to better control the concentration of escaping ammonia, the study on field testing of ammonia concentration in flue gas is carried nut by adopting the indophenol blue spectrophotometry. Taking the example of a 200-MW power plant in Inner Mongolia as the study case, the operation procedures and process of the indophenol blue spectrophotometry in the field testing are described in details. Then the comparison between the testing results and the online monitoring data is conducted with the impacts of the fly ash on the test results analyzed as well. The study results show that the concentrations of escaping ammonia can be obtained at different sampling points in the field test, whieh is helpful for ammonia spraying control. The presence of ash may enhance the absorbance of the samples substantially, which will cause higher testing result value. Therefore, for the sake of data accuracy, strict precautions should be taken to prevent ashes from polluting the samples in the sampling process.