NO_(x)分析仪转化效率的统计计算方法

Statistical Calculation Method of Conversion Efficiency of NO_(x) Analyzer

为了解决氮氧化物(NO_(x))分析仪转化炉转化效率的检测问题,对现有氮氧化物转化效率的计算模型进行了定量分析,结合计量工作中误差的含义,定义了氮氧化物分析仪检测过程中二氧化氮转化误差和一氧化氮检测误差两个概念;介绍了氮氧化物分析仪的非分光红外法检测原理和转化效率检测的必要性,采用臭氧发生器对氮氧化物分析仪进行转化效率检测,提出了基于二氧化氮转化误差和一氧化氮检测误差的转化效率二阶次计算模型,利用逐步回归原理确定模型中的自变量并进行参数估计。研究结果表明,相比于氮氧化物分析仪内嵌的计算模型和一阶次计算模型,本文提出的二阶次计算模型拟合方程的多重可决系数靠近1的程度平均提升了96.8%和51.5%,残差平方和平均降低了85.1%和31.7%,为提升氮氧化物分析仪的检测准确性提供了技术支撑。

In order to solve the problem of checking the conversion efficiency of the conversion furnace of the nitrogen oxide(NO_(x))analyzer,a quantitative analysis of the existing calculation model of the conversion efficiency of nitrogen oxides was carried out,and combined with the meaning of errors in the measurement work,two concepts of nitrogen dioxide conversion error and nitric oxide detection error during the detection process of nitrogen oxide analyzer were defined.The principle of non-spectroscopy infrared method detection of nitrogen oxide analyzer and the necessity of conversion efficiency check are introduced.The conversion efficiency of nitrogen oxide analyzer is checked using an ozone generator.A second-order calculation model of conversion efficiency based on the conversion error of nitrogen dioxide and the detection error of nitric oxide is proposed,and the principle of stepwise regression is used to determine the independent variables in the model and estimate the parameters.The research results show that compared with the calculation model embedded in the nitrogen oxide analyzer and the first-order calculation model,the degree of multiple coefficient of determination of the fitting equation close to 1 increased by 96.8%and 51.5%on average,and the residual sum of squares decreased by 85.1%and 31.7%on average,so that the nitrogen oxide analyzer can more accurately and reliably detect the concentration of nitrogen oxide in the exhaust gas of the vehicle.