基于TDLAS一次谐波的甲烷浓度检测系统及其温度补偿研究

本文结合甲烷1 653.72 nm波长2v3带R3支气体吸收线,分析温度变化对甲烷吸收线的谱线特性及甲烷气体浓度测量产生的影响。基于可调谐二极管激光吸收光谱与波长调制光谱技术,应用一次谐波信号检测甲烷气体的浓度,通过温度补偿抑制环境温度变化给检测带来的干扰。实验结果表明,研制的甲烷浓度检测系统的性能稳定,利用温度补偿系数校准后系统测量偏差在1%以内,可以有效地提高系统的检测精度。

TDLAS first harmonic based methane concentration detection system and its temperature compensation

We analyze the impact of temperature variation on the spectral characteristics of methane absorption line and the concentration measurement of methane gas with the absorption lines in R3 transitions of 2v3 band of methane at 1 653.72 nm.We detect methane gas concentration with first harmonic signal based on tunable diode laser absorption spectroscopy and wavelength modulation spectroscopy.We also suppress the interference of temperature Variation on detection accuracy by temperature compensation.Experimental results show that the methane detection system is stable.Its system measurement error is within 1％ after the calibration of temperature compensation coefficient,sotits system detection accuracy can be effectively improved.