分布式多点激光甲烷检测系统研究

摘要

针对传统甲烷检测系统存在的易受环境影响、检测精度低、稳定性差等问题,基于可调谐半导体激光吸收光谱技术和空分复用技术,设计了一种分布式多点激光甲烷检测系统.该系统采用波长1 653.7 nm的分布式反馈半导体激光器作为光源;利用谐波检测法得到二次谐波和一次谐波信号幅值比来反演甲烷浓度;采用1分8光分束器,并结合参考气室实现多个测点甲烷浓度的实时检测.在实验室环境下对该系统进行了测试,结果表明该系统测量准确性高、稳定性好,可实现10 km范围内测点的有效覆盖,在2.00％～85.0％甲烷浓度范围内,系统测量误差小于2％.%For problems of being easily affected by environment,low detection decision and poor stability in traditional methane detection system,a distributed multi-point laser methane detection system was designed based on tunable diode laser absorption spectroscopy technology and space division multiplexing technology.The system adopts distributed feedback semiconductor laser with wavelength of 1 653.7 nm as light source,uses ratio of the second harmonic and the first harmonic gotten by harmonic detection to invert methane concentration,and employs 1/8 beam splitter and reference air chamber to realize real-time multi-point methane concentration detection.The system has been tested in laboratory.The test results show that the system has high accuracy and good stability,can realize monitoring points within 10 km effectively covered,and measurement error is less than 2％ when methane concentration is 2.00％-85.0％.