基于近红外波段激光光谱吸收的丙烷探测研究

摘要

为了对石油气挥发性有机化合物的主要成分进行实时监测,实现石油化工行业的安全生产,采用激光光谱分析技术、利用宽谱光源分析了丙烷在1686.00nm~1687.00nm波段的光谱吸收特征,获得了吸收系数随波长变化的洛伦兹线型,其半峰半宽为0.21nm.选择中心波长为1686.30nm的分布反馈式半导体激光器作为光源,在丙烷宽谱吸收峰范围内进行波长扫描,得到了一次谐波信号和二次谐波信号随丙烷体积分数的变化规律,并在丙烷的体积分数0.0050~0.0300范围内标定了二次谐波与一次谐波信号的比值与体积分数的线性关系.结果表明,实验系统有很好的稳定性与重复性,能够进行实时的丙烷在线检测.该研究为探测其它挥发性有机化合物气体提供了理论及实验参考.%In order to real-time detect the main component of volatile organic compounds of oil gas and realize production safety in petrochemical industry, laser spectrum analysis technique was applied.Firstly, the broadband optical source was utilized to analyze the spectral absorption features of propane between 1686.00nm and 1687.00nm.The relationship between absorption coefficient and wavelength was fit into Lorentz lineshape, with half width at half max of 0.21nm.A distributed feedback laser with center wavelength of 1686.30nm was chosen as the sigle mode light source, and laser wavelength scan was made within wide absorption spectrum of propane.The changing regularity of the first and second harmonic signal with volume fraction of propane was acquired.The linear relationship between the ratio of the second harmonic signal to the first harmonic signal and propane volume fraction was calibrated with propane volume fraction from 0.0050 to 0.0300.The results show that, the system has good stability and repeatability, and can be used to do propane online detection.The study can provide the reference of theory and experiment for detecting other volatile organic compound gases.