基于傅里叶红外光谱仪的高温含水烟气中低浓度一氧化氮精确测量研究

Research on Accurate Measurement of Low Concentration Nitric Oxide in High Temperature Water-containing Flue Gas Based on FTIR Spectrometer

随着国家超低排放政策的深入,对烟气中污染物浓度精确测量提出了更高的要求。基于傅里叶红外光谱仪建立了高温含水条件下一氧化氮(NO)气体精确测量系统,在191℃条件下测量了含5%~20%水蒸气与摩尔分数为5~40μmol/mol NO混合前后的吸收光谱,通过修正混合物中H 2O的吸光度来精确确定NO浓度,并评价了系统测量不确定度。结果表明:NO在高温含水条件下测量结果与标准气体量值相对偏差小于1.8%,测量的扩展相对标准不确定度最大为2.8%(k=2),此系统具有良好的测量准确性和稳定性,对国家超低排放政策的执行和环保税的征收具有重要意义。

With the deepening of national ultra-low emission policy,higher requirements are put forward for accurate measurement of pollutant concentration in the flue gas.Based on Fourier transform infrared(FTIR)spectrometer,an accurate measurement system for nitric oxide(NO)gas under high temperature and water content was established.The absorption spectra of 5%~20%water vapor and 5~40μmol/mol NO were measured before and after mixing at 191℃.The NO concentration was accurately determined by correcting the absorbance of H 2O in the mixture,and system measurement uncertainty was evaluated.The results show that the relative deviation between the measurement result of NO in high temperature water-containing and the standard gas value is less than 1.8%,and the relative expanded uncertainty of the measurement is 2.78%(k=2).The system has good measurement accuracy and stability.It is of great significance to the implementation of the national ultra-low emission policy and the collection of environmental taxes.