提高NO测量精度的非线性补偿技术研究

Study on the nonlinearity compensation technology used for improving NO measurement accuracy

差分吸收光谱法(DOAS)应用于固定污染源烟气排放检测时,烟气的非线性吸收对测量气体浓度的准确性有很大的影响,必须对非线性吸收的影响进行修正。提出了一个新的非线性补偿方法,将反演浓度与实际浓度之比和反演结果之间对应关系拟合成非线性补偿函数,利用这个函数对浓度反演结果进行补偿。对6.67～673.66mg/m3范围内的NO气体实验研究表明,得到的非线性补偿函数能很好地修正非线性的影响,具有较高的气体浓度反演精度。

Differential optical absorption spectroscopy （DOAS） technique is widely used in monitoring the flue gas from fixed pollution source. However, the nonlinear absorption of flue gas has significant effect on the measure-ment accuracy,so it is necessary to correct the errors caused by nonlinear absorption. New nonlinear compensation method was proposed in this paper to improve the accuracy of DOAS measuring. By fitting the relationship between measurement result and ratio of measurement result to actual concentration,a nonlinear compensation function was ob-tained to compensate inversion result. This method was checked by monitoring the gas with NO concentration of 6.67-673.66 mg/m^3. Results showed that the obtained nonlinear compensation function could perfect revise the influence caused by nonlinear absorption,and the measurement results was in high precision.