光纤瓦斯多点传感系统的设计

Design of multipoint optical fiber methane sensing system

差分吸收法是基于近红外光谱吸收、远距离监测气体浓度的重要方法。采用双波长差分检测法,选取1 653.7 nm作为甲烷气体的吸收峰,1 652 nm作为参考波长,设计了一种新型远距离多点测量的光纤瓦斯传感系统,可以对甲烷气体浓度进行实时检测。通过对光路链路损耗的预算及吸收系数的计算,综合考虑气室结构和数字信号处理电路等影响系统性能的重要因素,从理论上论证了该方案的可行性。系统的稳定性及测试灵敏度需通过实验验证,仍有较大的提高空间,同时也可用于实现其他气体浓度的监测和远程监控。

Differential absorption measurement is an important method for gas concentration remote monitoring based on the near infrared absorption spectroscopy.In this paper,a novel multipoint optical fiber sensing system for methane monitoring was constructed.Two laser sources were adopted in the system,one wavelength was 1 653.7 nm which was selected as the absorption peak of methane,and the other wavelength was 1 652 nm which was used as the reference wavelength.The system could be used to detect the concentration of methane in real-time.By analyzing the loss of the whole optical path and the calculation of absorption coefficient,and considering the influence of these factors on the system performance,such as the gas chamber structure and the digital signal processing circuits including lock-in amplifier,the feasibility of the methane sensing scheme was theoretically demonstrated.The system can also be used for remote monitoring of many other gas.