Research on Fiber Methane Sensing System Based on Prism Gas Cell
WU Xi-jun1, WANG Yu-tian1, LIU Xue-cai1, LI Shu-jun2
1. Measurement Technology and Instrumentation Key Lab of Hebei Province, Yanshan University, Qinhuangdao 066004, China 2. Shijiazhuang Water Resources and Hydrology Reconnaissance Bureau, Shijiazhuang 050018, China
Abstract：A novel fiber methane detection system was constructed based on integration of prism gas cell and harmonic detection technique. The system can be applied to broad-range concentration detection. Grounded on the Beer-Lambert approximation, the detection of various concentration (0-20%) of methane was completed using subtraction of background and ratio processing method, as the atmosphere surroundings was treated as background. The direct absorption spectra for various concentration were measured using GRIN gas cell, combined with available DFB-LD, and the R5 line of the 2ν3 band of methane was selected as absorption peak. The system was tested online during gas mixing process and the linear relation between system indication and concentration variation was validated, while the stability and dynamic response characteristics was confirmed by experiments. The system sensitivity can be adjusted according to the concentration level of various field environments by changing the prism distance using step motor. So that, the system can be applied to various application fields and can be adopted as a monitoring instrument for coalmine tunnel and natural gas pipeline.
Key words：Fiber sensing;Methane detection;Prism gas cell;Harmonic detection
吴希军1，王玉田1，刘学才1，李树军2. 基于棱镜气室的光纤甲烷传感系统的研究[J]. 光谱学与光谱分析, 2010, 30(05): 1434-1438.
WU Xi-jun1, WANG Yu-tian1, LIU Xue-cai1, LI Shu-jun2. Research on Fiber Methane Sensing System Based on Prism Gas Cell. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2010, 30(05): 1434-1438.
